This study analyzed kinematic changes during a 100-m front crawl to investigate the effects of performance level and gender, comparing high-speed males (N = 12), medium-speed males (N = 8), low-speed males (N = 8), and high-speed females (N = 8). Assessments were made throughout a race in a 25-m pool divided into five 5-m zones. Velocity, stroke rate, and stroke length were calculated for each 25-m length and for each 5-m zone. Four stroke phases were identified by video analysis, and the index of coordination was calculated. Three modes of arm coordination were identified: catch-up, opposition, and superposition. The leg kick was also analyzed.

High-speed males were distinguished by higher velocity, stroke rate, stroke length, propulsive phase, and index of coordination, and by the stability of those factors throughout the race. The medium- and low-speed males had an opposition coordination during the third length of the four lengths. Because of fatigue in length 4, more time was spent in the hand-push phase (possibly because of a decrease in hand velocity) and a change to superposition coordination. This change was ineffective, however, as stroke length continued to decrease throughout the 100 m. The main gender findings were the greater stroke length of the males compared to the females and the similar index of coordination of both high-speed groups.

Implication. The high-speed swimmers were characterized by higher and more stable stroke length and index of coordination. The principal gender effect was greater stroke length in the males than in the females.